A group keeps recruiting people who resemble its existing members, even though nobody has written a rule requiring that resemblance. Members invite friends, share opportunities in familiar places, and feel comfortable with people whose experiences they recognize.
Homophily describes the tendency for similar people to be connected. It can reflect preferences, but also geography, workplaces, schools, and other circumstances that determine who has opportunities to meet. A pattern of similarity does not by itself identify the cause.
The network shapes what becomes available
Once relationships form, they carry information and introductions. If a professional circle is socially narrow, opportunities may circulate among people with similar backgrounds long before any formal selection begins. An open application process cannot entirely undo that earlier distribution of access.
Similarity can make communication easier and support trust, but it can also reduce the range of experience a group encounters. Members may mistake familiar assumptions for obvious truths because few people around them have reason to question them.
Understanding homophily requires looking at both choice and opportunity. Where do people meet, who feels welcome there, and which relationships persist? Changing only the language of an invitation may accomplish little if the settings through which relationships develop remain unchanged.